Breivik wrote a 27-page letter addressed to prison officials, a copy of which was obtained by The Associated Press on Friday.

“If it wasn’t for the fact that I am an exceptionally patient person, I would most likely have lost my mind in pure frustration,” Breivik said in the letter dated Oct. 15 that was updated on Oct. 26 and Oct. 30. “Anyway, there are limits to what a person can take.”

Breivik wrote that he is frustrated that guards do not cooperate with his carefully planned daily schedule, where he times his various activities down to the minute.